1. Field of the Invention
The present invention is generally directed toward automobile audio systems and, more particularly, toward partitioned audio systems wherein front passengers and rear passengers listen to different audio sources.
2. Description of the Related Art
Most of the time in automobiles, all of the passengers listen to the same audio source (radio/tape/CD) whereby sounds are emitted to the passenger compartment from the front and rear speakers. However, there are times when the rear passengers cannot agree with the front passengers on the desired music or radio station to be listened to. In these situations, it is desirable to have a partitioned system wherein the front passengers listen to one source via the front speakers while the rear passengers listen to a different source by means of headphones or other personal sound sources.
Such partitioned systems are generally well known in the art. When the system is operated in the single-source mode (i.e., partitioning disabled), the front and rear speaker output is entirely controlled by the conventional controls positioned on or near the front dashboard of the automobile. In this situation, the front passengers have total control over speaker output, the portion of the overall sound attributed to the front speakers and to the rear speakers, and the total overall sound level. When the system is operated in the dual source mode (i.e., when sound partitioning is enabled), adjustment of the dashboard mounted controls by the front seat passengers is only operable to adjust the volume of the front speakers, the rear speakers being turned off. Rear-seat accessible controls are used by the rear passengers to adjust the audio source and volume output by the headphones.
Unfortunately, when the system is disabled/enabled to switch between single source and dual source modes, volume stability problems arise. For example, when switching from a single source to dual sources, the volume perceived by the front passengers drops considerably. Conversely, when switching from dual source to single source modes, the volume perceived by the front passengers increases significantly. This disadvantage with state of the art systems is aggravating and causes the front seat passengers to have to adjust the volume controls each time the mode of operation is changed.
Therefore, there exists a need in the art for a partitioned audio system that maintains the volume, as perceived by the front-seat passengers, at a stable level when the system is switched between single and dual source modes.